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| author | Peter Hutterer <peter.hutterer@who-t.net> | 2015-08-27 13:13:47 +1000 |
|---|---|---|
| committer | Peter Hutterer <peter.hutterer@who-t.net> | 2015-09-11 00:54:01 +1000 |
| commit | 8d9e7a1bcf8eac3a344d8c1135b2b546c37e8b04 (patch) | |
| tree | 72229c2a0e52505bfc90f8f3ea2063ead02fd3a4 /doc | |
| parent | 0c7ef582ebeceb567b2972de2163e9156c7b6283 (diff) | |
Add an API to change pointer acceleration profiles
The quartett of new config functions is:
libinput_device_config_accel_get_profiles
libinput_device_config_accel_get_profile
libinput_device_config_accel_set_profile
libinput_device_config_accel_get_default_profile
The profile defines how the pointer acceleration works, from a very high-level
perspective. Two profiles are on offer, "adaptive", the standard one we have
used so far and "flat" which is a simple multiplier of input deltas and
provides 1:1 mapping of device movement vs pointer movement.
The speed setting is on top of the profile, a speed of 0 (default) is the
equivalent to "no pointer acceleration". This is popular among gamers and
users of switchable-dpi mice.
The flat profile unnormalizes the deltas, i.e. you get what the device does
and any device below 800dpi will feel excruciatingly slow. The speed range
[-1, 1] maps into 0-200% of the speed. At 200%, a delta of 1 is translated
into a 2 pixel movement, anything higher makes it rather pointless.
The flat profile is currently available for all pointer devices but touchpads.
https://bugs.freedesktop.org/show_bug.cgi?id=89485
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/pointer-acceleration.dox | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/doc/pointer-acceleration.dox b/doc/pointer-acceleration.dox index a372e15..7ec5e74 100644 --- a/doc/pointer-acceleration.dox +++ b/doc/pointer-acceleration.dox @@ -9,6 +9,16 @@ This page explains the high-level concepts used in the code. It aims to provide an overview for developers and is not necessarily useful for users. +@section ptraccel-profiles Pointer acceleration profiles + +The profile decides the general method of pointer acceleration. +libinput currently supports two profiles: "adaptive" and "flat". The aptive +profile is the default profile for all devices and takes the current speed +of the device into account when deciding on acceleration. The flat profile +is simply a constant factor applied to all device deltas, regardless of the +speed of motion (see @ref ptraccel-profile-flat). Most of this document +describes the adaptive pointer acceleration. + @section ptraccel-velocity Velocity calculation The device's speed of movement is measured across multiple input events @@ -107,4 +117,11 @@ The image above shows the trackpoint acceleration profile in comparison to the @ref ptraccel-linear. The constant acceleration factor, usually applied by udev, shapes the acceleration profile. +@section ptraccel-profile-flat The flat pointer acceleration profile + +In a flat profile, the acceleration factor is constant regardless of the +velocity of the pointer and each delta (dx, dy) results in an accelerated delta +(dx * factor, dy * factor). This provides 1:1 movement between the device +and the pointer on-screen. + */ |